The present invention relates to an antenna device in a radio transmitter and receiver, and more particularly, to an apparatus for rotating and driving an antenna device to direct an antenna element thereof in a desired direction.
In fishery radios, amateur radios and the like, the position of the other office is unspecified. In order to make an exchange of communication with an optional office of such unspecified offices, it is necessary to release a beam having a directivity towards the object. Therefore, a multi-element antenna device is designed so as to be rotated by a rotating and driving apparatus. On the other hand, it is necessary to release a beam having a sharp directivity towards the object in order to make an exchange of communication with the remote other office. To this end, the number of elements of the antenna device need be increased. Accordingly, the antenna device itself increases in weight and accordingly, the driving torque of the rotating and driving apparatus has to be increased. Thus, there has been used a rotating and driving apparatus having a driving torque corresponding to the weight of each of the antenna devices which are different in weight. Therefore, it is necessary to prepare the rotating and driving apparatus corresponding to the weight of each of the antenna devices. In the case where the number of antenna elements of the existing antenna device is increased or decreased, the rotating and driving apparatus has to be exchanged and thus the existing antenna device needs to be disassembled, which requires labors and is uneconomical.